An improved tracking dirrerentiator capable of compensating phase lag

An improved tracking differentiator(ITD) is proposed for processing the signal with noise. Tracking differentiator(TD) is a kind of low-pass filter utilized in many industrial control systems for its advantages: simple structure, model-independence, and so on. TD not only has the function of filtering the signal, but also can provide derivatives of the signal at the same time. Like most low-pass filter, TD have the same disadvantage: producing the phase lag while eliminating the noise. ITD presented in this paper is to solve this problem. By the frequency domain analysis, the filtering effect of the ITD is discussed. The result is compared with the TD filter. Both the theoretical analysis and the simulation results indicate that the ITD obviously decrease the phase lag, and has the better tracking accuracy.